If carbohydrate malabsorption is linked to depression as suggested here, and with a pretty clear causal pathway outlined in the abstract;

“Incompletely absorbed sugars may form nonabsorbable complexes with tryptophan, an amino acid precursor of serotonin, decreasing its availability. As serotonin is the most important neurotransmitter involved in depressive disorders, its depletion could lead to the onset of depression.”

then mystery solv-ed!

Yesterday I had my oh-so-familiar onset of the afternoon blues. It arrived at 4.10pm and lasted about 10 minutes.
AMAZING!!!

At this point in the Elsie Hogfat experiment I can say with confidence that I don’t think we’ll ever go back to eating sugar and flour again.